A storage apparatus is an apparatus including a storage medium such as a hard disk drive (hereinafter, “HDD”) or a solid state drive (hereinafter, “SSD”) and providing a storage area for data to be processed by an application and other programs running on a host computer or the like, and is also referred to as a disk subsystem.
In recent years, there has been an increasing demand that information apparatuses should save power consumption more than ever. In this regard, storage apparatuses have been also required to accomplish power consumption saving, space saving, high-density packaging, and noise reduction.
One of the great challenges for meeting these demands is how to control operations of a large number of electric cooling fans (hereinafter, simply called “fans”) provided for cooling internal devices in a storage apparatus. Conventionally and generally, fans provided in a storage apparatus are controlled to start operating upon powering the storage apparatus on, and to always operate at the maximum rated speed while the storage apparatus is running. Such control method, however, poses a problem that, all the time during the operation, all the fans consume the maximum amount of power regardless of the surrounding environment, operating status and other conditions of the storage apparatus. In addition, other problems also arise that all the fans always generate the maximum operating noise, and that, all the time during the operation, the maximum mechanical load is applied on mechanical components such as a bearing included in a revolution mechanism for each of the fans, which in turn deteriorates the mechanical components and consequently shortens the lifetime of the fan.
In this regard, Patent Literature (PTL) 1 proposes a configuration capable of switching an operating state of a fan between high-speed revolution and low-speed revolution according to an operation mode of a control device to be cooled by the fan.